Add a warning about the status of this document

Author: zcorpan

geometry/Overview.bs

@@ -42,6 +42,10 @@ This specification describes several geometry interfaces [[!WEBIDL]] for the rep
 
 The SVG interfaces SVGPoint, SVGRect and SVGMatrix [[SVG11]] are aliasing the here defined interfaces in favor for common interfaces used by SVG, Canvas 2D Context [[2DCONTEXT]] and CSS Transforms [[!CSS3-TRANSFORMS]].
 
+Issue: The IDL in this specification is currently in an experimental state.
+An <a href="https://lists.w3.org/Archives/Public/public-fx/2015AprJun/0001.html">approach</a> of avoiding overloading in constructors and instead using factory static methods, and supporting dictionary types everywhere, is explored.
+Readers interested in a specification that more closely matches implementations as of April 2015 are referred to an <a href="http://www.w3.org/TR/2014/WD-geometry-1-20140522/">earlier revision of this specification</a>.
+
 <h2 id='DOMPoint'>
 The DOMPoint interfaces</h2>